Arylsulfonyl methyl isocyanides

Among the a-acidic isocyanides, isocyano esters (1) (for the first isolated example of a-acidic isocyano ester see [24]), isocyano amides (2) (for the first isolated example of a-acidic isocyano amide see [25]), and arylsulfonyl methyl isocyanides (3) (for the first report of TosMlC see [26]) have been studied predominantly, and therefore this mini review will mainly focus on the MCRs involving these species. 

Fig. 3 General methods for the preparation of isocyano esters (1), isocyano amides (2), and arylsulfonyl methyl isocyanides (3) (R = afkyl and/or H)...

Arylsulfonyl methyl isocyanides (3) and isocyano esters (1) can also be prepared by the deprotonation of alkylisocyanides (5) by strong bases (nBuLi or NaH) followed by the addition of TosF and dialkyl carbonates or ethyl chloroformate, respectively (pathB) [37, 38]. However, the use of small and foul-smelling alkyl isocyanides makes this route less attractive. 

For arylsulfonyl methyl isocyanides (3), [3 + 2] cycloadditions with aldehydes yielding 4,5-disubstituted oxazoles (N) have been reported [115]. The cycloaddition takes place in the same manner as with the use of isocyano esters (A, = H) ... 

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